Physics Dept. Demonstration Manual

DF03 - Bernoulli's Principle, Venturi


To show pressure differential along a tube of changing diameter. Illustrates the presence of higher pressure on either side of a constriction.

  • Venturi tube mounted horizontally
  • 4 manometers
  • Air supply (vacuum cleaner, or lab air supply)
  • Special hose attachment(s)


The relative pressures are indicated by a four tube manometer filled with colored water and attached to the Venturi tube. When airflow is present, the water in the constriction area assumes a lower level than the outside tubes because of the lower pressure.